My direct debit is for a completely different amount than my contract

I took out a new 18 month contract in November to renew at a similar level to the previous year (around £103). I have been with Virgin for 20+ years and was satisfied with that.  However when checking my online account in December the bill was showing at 50% more than the contract I had agreed (£147.95). I spoke to customer service and escalated it through many phone calls. I was told they had no record of my November contract on their system so I was just on a standard rolling contract?????   

So I emailed copies of the new November contract to a supervisor (whose email address was given to me) and they said the only way they could resolve was to reissue a further contract (this was in December) and then apply a monthly credit to bring it down to the original value of the original November 2024 contract. 

In January I was billed for the new December contract, minus the promised credit so it equalled the original November contract. That was okay. Great stuff.  HOWEVER, I have just had my latest bill for February and it is showing the December contract of nearly £`147 PLUS an unpaid amount of £63.95 (which was the credit that was applied to my account to ensure it then equalled the November contract). PLUS £7.50 late payment charge !!!!  EQUALLING £213.90!!!  Billing customer service have no idea how to deal with complex issues like this. Who can sort this out as it is totally unacceptable levels of stress being caused.  We need to rapidly resolve